This invention relates to a doctor blade device having a doctor blade secured in a pivoting holder for engagement at an adjustable angle with an inked roll, such as the gravure image carrier cylinder of a gravure printing press.
In a doctor blade device for a gravure press as disclosed in German patent publication 1,941,595 A, the doctor blade holder is able to pivot on a doctor blade carrier along a circular arc centered on the knife edge of the doctor blade, so that when the doctor blade holder is pivoted there is an alteration of the angle of the doctor blade relative to the gravure image carrier cylinder which takes place without changing the line of contact of the doctor blade on this cylinder.
If inks of different viscosity and different drying properties are processed, it is not only the angle of engagement of the doctor blade on the cylinder but also the position of the line of contact of the edge of the doctor blade on the cylinder which are important, since this position affects the drying of the ink. Thus while the position of the line of contact of the doctor blade on the gravure image carrier cylinder affects the degree of drying, the degree of filling of the etch depressions in the cylinder with ink depends on the engagement angle of the doctor blade. In order to effect high quality printing it is therefore not only necessary to set the engagement angle of the doctor blade but also the position of the line of engagement of the doctor blade on the cylinder right from the start of a run.